Today was one of the more complex trading days we've had recently.  Three things were certainly in play and 2 of them were interdependent. 

1. Stocks
2. Trump's Press Conference
3. 10yr Treasury auction

Bonds weren't doing much of anything until stocks opened.  Granted, stock futures trade all night, but the 9:30am NYSE open nonetheless marks a major liquidity event.  This can spill over to bonds if money managers are adjusting asset allocation or if bond-specific exchange-traded funds (ETFs) are active.  In today's case, the NYSE open pushed bond markets to their weakest levels of the day as stocks advanced to the day's best levels.

Trump's press conference made for a complete reversal of that trade (stocks and bond yields went lower together.  The rationale being passed around the campfire is that investors were hoping that Trump would do more to address fiscal stimulus plans.

Bonds were at their best levels of the day as the 10yr auction approached, but were noticeably hesitant to make any further gains until the results.  The auction ended up being incredibly strong, which may have done more harm than good by the end of the day.  Reason being: the auction left no doubt as to what traders should be doing (i.e. BUYING BONDS).  The feeding frenzy was instantaneous, bringing yie.lds to their lowest levels since Nov 30th (true story!).  

And then it was over.  10yr yields broke the 2.34% technical level, but anyone who was a buyer was out within minutes following the auction.  We should also consider that stocks staged an afternoon rally to new session highs.  Either way, yields moved reasonably quickly back to pre-auction levels and 10s ultimately ended the day just barely into positive territory.  Fannie 3.5 MBS performed just slightly better, gaining nearly an eighth of a point by the end of the day.  Rate sheets were in the best shape since Nov 17th for most lenders, but not too far off last Thursday's.